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CHARLES M. DABCLL, CF NEW LCNDCMCCNNECTICU", AssIeNCn TC 'IIIIiA WILSON IvIANUFACTURING COMPANY, CF SAME PLACE.

Letters .Patent No. 75,870, dated March 24, 1868.

IMPROVEMENT 'IN BRACES'PCR BITS.

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TO .ALL WI-IOM IT MAY GONOERN:

Beit known that I, CnAItLEs M. DAIsoLL, of New London, in the countyof'New London, and State of Connecticut, have invented a new and useful Improvement in Braces for Bits; and I do hereby declare that thc following lis a full, clear, and exact description thereof, which will enable those skilled in the art to make and uso the same, reference boing had to the' accompanying drawings, forming part of this specification.

This 'invention relates to the manner in which the bit is fastened and held in the brace; and it consists in a tubular female screw or nut, et' novel formation, and in two, or more jaws or clamps, which are operated by tho nut, whereby thc bit is firmly' secured in the brace, and easily detached therefrom, as will hereinafter be described.

Figure 1 represents tho end ofthe brace with the nut oi',l in order'to show to better advantage the form of the clamp.

Figure 2.is a section of the fasteningend of the brace, wi-th the shank of an auger-bit-fastened according' to my invention.

Figure 3 is a View of tho outer ends of the clamps.

Similar letter-sof reference indicato corresponding parts.

A represents apart-ion of the brace, it being the fastening-end; B is the tubular nut; C represents the clamps; D is the auger-bit. The end of the brace isi-formed with an'oriec sufficiently large-to admit thc end of any ordinary anger er other bit; .and the clamps C are so attached that they have suiiicient play or open suilieiently wide to efhcloseand hold the largest 4size of auger-bits, as well as' the smallest pod or gimlet-bit. In fig. 1 a. side view of one of the clamps is seen. The inncnend is in a T-form, and is'Sunken into thc brace, so that its'baclc or outer surface is flush with the brace, or so that it may heforeed inward from the surface ofthe brace (as would be necessary in holding a very small bit) as far as theende'` the brace or the line marked a. This T-end is simply dropped inte the recess prepared for it, when it .is held bythe nut B, as seen in fig. 2. The peculiar shape of the-outer portions of 'these clamps will also be noticed inthe same figure: The portion b of the T-end acts as a hinge upon which theclamp works.` The nut B is flaring at its outer end, as seen in the drawing, so that when it is screwed or turned up towards the clamp, it strik-es the inclined surfaces of the clamps, and forces them together or towards eachother. The clamps are cut out on their inner sides, so that they admit the enlarged or angular portion offthe shank of Ath'e bit, but close up upon the bit, as seen, when forced in by the nut. When .there is noshankor hit between the clamps, vthe nut will force lthem in contact with Ieach other, when their .outer ends will present the appearance seen invfig. 3. By turning back the nut B, the clamps are expanded4 suihfeientlygto admitthe largestsize of augerbit without being displaced, but they are readilyY detached by turningthc nut 'l ia .ck` past' them. i' I Y It will bc seen, from this formation' and arrangement, that the scrdw-thread of the nut B is not brought in contact withthe clamps, and ofcourse it cannot be injured thereby.

I donot4 claim fastening the jaws to thcstock -by pivots or fixed pins, as lI am aware this has already been done; but` having thus deseribedlmy invention, v

I' claim as new, and desire to secure by Letters Patent- 1. The jaws C, constructed asdescribed, having a lsenriicirculur hase inelinng outward, and provid-ed with thc T-shaped shank, fitting without pivots in the T-slot'ot'. the stock A, as herein described, for the purpose specified.

2. The jaws G,`const ru'c tcdas described, in combination with thcserew-nut B, when the inner inclined surface of such-nut bears equally at all peints around the inclined circumference of the jaws C, provided with the T-shanks, as herein described, for the pnrposcspcciied.

3. The stock A, when provided with the-T-slot, adapted to receive the T-,shank of the jaws C, in con'ibinntion with the nut B, whose screw-thread is nbojvc thejaws, as herein described, for the purpose specified.

y CHARLES M. DABCLL.

Witnesses:A

NATHAN BLcIInn, E. '1'. BROWN. 

